Magnetic recording media, for longitudinal and perpendicular recording, typically require an overcoat for wear and corrosion protection. The overcoat protects the magnetic thin-film layer at its inner-diameter landing zone from damage when the transducer head contacts the disc during a stop-start cycle. In the outer, data zone of the disc, the overcoat functions to protect the disc from environmental factors, such as oxidation or humidity, that can lead to corrosion.
The protection provided by the overcoat is related, in part, to its thickness, where a thicker overcoat offers better wear resistance than a thinner overcoat.
However, a thicker overcoat limits the flying height of a magnetic head on a disc, creating a spacing loss that in turn limits the recording density of the disc.
Therefore, it is an object of the invention to provide an overcoat that has adequate thickness to offer good wear resistance in the landing zone and also allow the head to fly closely to the medium to minimize spacing loss in the data zone.